Burglar-alarm



BURGLAR ALARM.

No. 302,581. Patented July 29,1884.

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WITNESSES. if INVENTORS. O4 BY ATTORNEY 4|. PETERS. Mo-Lmgnyhcr, wahinmun. ac.

rvirnn Sra'rns rmnnt I mam LEONARD D. NORTH, HANNIBAL H. INGHAM, AND FRANK W. IN GI-IAM, OF CHICAGO, ILLINOIS.

BURGLAR ALA'RIl/l.

SPECIFICATION forming part of Letters Patent No. 302,581, dated July 29, 1884. Application filed September 5, 1883. (Model.)

State of Illinois, have invented new and useful Improvements in Burglar-Alarms, of which the following is a specification, reference bemg had to the accompanying drawings, illustrating our invention, in which-- Figure 1 is a plan view of a mechanism embodying our improvements,with the cover to the gearing-case removed and the escape pendulum held inplace by the trigger on the knobshank; Fig. 2, the same mechanism in position as when the alarm is being sounded; Fig. 3, a side elevation of the device.

The present invention relates to an improvement in that class of devices which are to be attached to the inside of doors, and sound an alarm by the turning of the knob to the catch.

The nature of the present invention consists in an alarm-case pivoted to the door and con- I nected with a spring, so that the turning of the door-knob will release the trigger from the alarm-detent and allow the case to swing so far to one side that the trigger will be free from the detent during the sounding of the alarm, and remain in that position till the case is readjusted.

A represents a plate of thin metal,which is fastened to the door by screws, and serves the purpose of preventing the door-surface from being marred, and the extension part B from the introduction of an instrument through a hole in the door, to prevent the alarm-detent G from vibrating when the knob Dis turned.

To illustrate: a a represent the height of the case to the catch-lock, and the dotted line 1) represents where an instrument might be put through the door to stop the movement of the alarm-detent O, notwithstanding the trigger E should be released, as at Fig. 2, if it were not for extension 13 on plate A.

F G represent the case which supports the ordinary clock alarm apparatus, 0 'd cf 71.

G is the cover to the case, hinged so as to swing open, as shown by dotted lines G, and be held in place by a pin, 9, put through the winding-post 71, as shown at Fig. 3. The case at its upper end is somewhat elongated at H,

that it may by a screw be pivoted to the door, a portion of which is shown at L, with doorlatch M and knob D attached. A spring, N, is attached at each end, respectively, to the door is the means by which the latter is moved to one side when the trigger Eescapes the pendulum-lever O. The trigger E is of ordinary construction, and is held to the shank of knob D by ordinary meansin this instance by the same screw, P, which holds the knobshank to the spindle, and of a proper length and in po sition to engage the lower end of lever O. The stop-post J is of the same size as the windingpost h, so that the same key may be used on both 5 and in the elongated part I of the case and to the post is attached a stop, K, which, when turned in a horizontal position,holds the alarm-detent in a fixed position, and when turned to a vertical position, as shown at Figs. 1 and 3, allows the alarm-detent to vibrate, and consequently sound an alarm. The case with the alarm therein being attached to the door, as specified, the stop K is set in a horizontal position, as shown by dotted lines B, Fig. 1. The works are then wound and the trigger placed against the alarm-detent G on the side shown at Fig. 1. The stop K is then turned down. This sets the alarm so that the turning of the knob D to withdraw the knoblatch M will disengage the trigger from the alarm-detent and sound an alarm, the device then beinginposition shown at Fig. 2. Vhere no alarm has been sounded and the door is to be opened, the stop K is to be turned upward and the knob D turned to disengage the trigger, and the alarm will be swung by the L and to the lower portion of case F G I, and

spring N to one side, so as not to interfere with the free movement of the knob D.

It is well to state that the back plate is not an essential feature in the working of the alarm, but protects the door and prevents tampering with the pendulum from the out side, and forms a part of a better construction in this kind of device.

In the foregoing we have shown and described the principal mechanism of a burglaralarm, to the better understanding of our improvement, but confine ourselves to the pivoted case and attachments as claimed, inasmuch as it has been common in stationary cases to operate an alarm mechanism by the turning of the door-knob.

We claim as new and desire to secure by Letters Patent r The case F G, supporting the alarm devices and pivoted to the door at H, in combination with the trigger E, attached to the door-knob shank, the lever 0, attached at one 10 end to the anchor of the alarm mechanism,

and the spring N, attached to the door and'to the swinging case, to bring the latter to one side when the free end of lever O is disengaged from trigger E, as specified.

LEONARD D. NORTH. HANNIBAL H. INGHAM. FRANK W. INGHAM. Witnesses:

G. L. OHAPIN, J. S. HUEY. 

